Hiroshi has been absorbed with fishing since he was a child because his family runs a fishing tackle shop in Yokohama. People around Yokohama and Yokosuka used to call him a "prodigy." He has had a 15-year fishing career since then. At the age of 21, he is dedicating himself to teaching others the art of fishing as a leisure activity. He is a staunch fisherman. Because of his obsession with fishing, he doesn't know much about the world, and often gets involved in trouble at the harbor.

When Ryo Hazuki enters the harbor when searching for Master Chen, he encounters Goro Mihashi and Tetsuya Nagashima mugging Hiroshi. Ryo stops them and saves him. Hiroshi is very grateful for his help and is willing to help him out whenever he needs it.

Hiroshi suspects that the punk who tried to mug him is one of the Mad Angels, although this is not true.